Thermostable amylolytic enzymes of thermophilic microorganisms from deep-sea hydrothermal vents

Microorganisms growing above 60 degree C isolated from deep-sea hydrothermal vents were screened for amylolytic activity. Of the 269 strains tested, 70 were found to be positive. Nine archaea (including Thermococcus hydrothermalis AL662 and Thermococcus fumicolans ST557) and one thermophilic bacterium were selected for the determination of thermostability, and the temperature and pH optima of their amylolytic enzymes. Pullulanase, alpha -glucosidase and alpha -amylase activities were detected in four archaeal strains (including AL662 and ST557) related to the genus Thermococcus. The anaerobic hyperthermophilic archaeon, Thermococcus hydrothermalis was chosen for the further study of the alpha -glucosidase activity, and a preliminary characterization of this enzyme was carried out. The small number of highly thermostable alpha -glucosidases that has been described to date, combined with the very interesting properties of this enzyme, suggest a use for this enzyme in biotechnological processes.